The association of Schistosomiasis mansoni and proteinuria in an endemic area. A preliminary report.

The association of Schistosoma mansoni infection and proteinuria was investigated by measuring quantitative urinary protein in a defined population in an endemic area in northeastern Brazil. Persons with schistosomiasis had higher mean urinary protein than those without. Two of 162 persons with schistosomiasis had clear evidence of renal disease (pathologic proteinuria, abnormal urinary sediment). These results seemed to be related neither to the intensity of S. mansoni infection as measured by fecal egg excretion nor to the presence of hepatic and splenic enlargement in schistosomiasis.

The intensity and effects of infection with Schistosoma mansoni in a rural community in northeast Brazil.

The intensity of infection with Schistosoma mansoni and its effects were investigated in a defined population living on three contiguous fazendas (subcounties) in a nonmalarious area of northeast Brazil near Salvador, Bahia. Quantitative stool egg counts (Bell technique) were performed on 363 of 417 individuals (90%) of all ages; physical examinations were done on 294 of 357 individuals (82%) 5 years of age and older. The maximum increase in prevalence was observed between the 1- to 4- and 5- to 9-year age groups, while the maximum increase in fecal egg count occurred between 5- to 9- and 10- to 14-year age groups. Highest egg counts were observed in the 10- to 14-year age group (geometric mean of 301 eggs per ml of stool) while the maximum prevalence (100%) was in the 20- to 24-year age group. In the fazenda with the lowest quantitative egg counts the age specific prevalence rates increased more slowly than in the fazendas with higher egg counts. In the study group nearly 50% of the total fecal egg output was accounted for by 22 individuals (6%) who had a mean age of 12.6 years. Egg counts for this selected group were all over 800 eggs per ml of stool with a mean of 1,514 eggs per ml of stool. In children under 15 years of age, the frequency of hepatomegaly and splenomegaly varied directly with the egg count; further, the degree of hepatomegaly was directly correlated with increasing egg counts. No splenic enlargement was noted in children not excreting eggs. In adults, on the other hand, neither splenomegaly nor hepatomegaly could be directly related to schistosomal infection per se. In children, neither the presence of infection with S. mansoni nor its intensity was reflected by altered anthropometric measurements. In the one fazenda tested the frequency of stools positive for occult blood correlated with increasing S. mansoni egg counts.

House construction, triatomine distribution, and household distribution of seroreactivity to Trypanosoma cruzi in a rural community in northeast Brazil.

Household distribution of seroreactivity to Trypanosoma cruzi in inhabitants was analyzed in relation to house construction and the distribution of Panstrongylus megistus, the principal domestic vector of Chagas' disease in a rural area in northeast Brazil. No children residing in mud-brick houses were seroreactive to T. cruzi. The highest rates of seroreactivity occurred in residents of unplastered mud-stick houses, and were twice as high as those found in persons living in mud-brick houses or plastered mud-stick houses. Two-thirds of seroreactive children in this area resided in unplastered mud-stick houses. Over 90% of the P. megistus infestations were found in mud-stick houses. Mud-brick houses had the lowest infestation rates of P. megistus and the lowest household rates of seroreactivity to T. cruzi.

Trypanosoma cruzi infection in dogs and cats and household seroreactivity to T. cruzi in a rural community in northeast Brazil.

The prevalence of Trypanosoma cruzi parasitemia as determined by xenodiagnosis on domestic dogs and cats was correlated with household rates of seroreactivity to T. cruzi and household Panstrongylus megistus infestation in a rural area in northeast Brazil where P. megistus was the only domiciliary triatomine vector. T. cruzi infection was present in about 18% of domestic dogs and cats. Two-thirds of seroreactive children below age 10 resided in houses with T. cruzi-infected animals. In houses with a T. cruzi-infected dog or cat, as well as at least one infected P. megistus, the household rate of seroreactivity to T. cruzi was five times greater than in houses with non-infected domestic animals and no infected triatomine vectors. Domestic dogs and cats are important reservoirs of T. cruzi in an endemic area where P. megistus is the only domiciliary triatomine vector.

The epidemiology and household distribution of seroreactivity to Trypanosoma cruzi in a rural community in northeast Brazil.

The prevalence rates and household distribution of seroreactivity to Trypanosoma cruzi by complement fixation (CF) and indirect immunofluorescent antibody methods were determined in a population of 1,087 persons living in a rural area endemic for Chagas' disease in northeast Brazil. There was a gradual rise in the rate of seropositivity to 60% by age 20. Between ages 20 and 55 the prevalence rate remained at about 60%, but declined thereafter. The decline in the older age groups was not accompanied by a fall in geometric mean titer, suggesting that the decline might better be explained by an increased mortality among those seropositive than by a decrease in CF reactivity associated with age. There was variation in the rates of seropositivity in children among the geographic subunits, but the rates among adults were fairly uniform. Household clustering of seropositivity was demonstrated when both household size and age distribution were taken into account. The presence of a seropositive child less than 5 years of age was a good indicator of a household with a high rate of seropositivity; screening for young seropositive children might be a useful tool to locate high risk households. Seropositive children in households where the mother was seropositive but the father seronegative were significantly younger than seropositive children in households where the father was seropositive but the mother seronegative even though the age distribution and the overall rate of seropositivity in both groups of children were similar; thus, conversion to seropositivity earlier in life in children of seropositive mothers may not be due solely to increased exposure, but may indicate that the immunologic response in such children differed from that of children from seronegative mothers.

A three year follow-up of chemotherapy with oxamniquine in a Brazilian community with endemic schistosomiasis mansoni.

Oral oxamniquine was tested as a control strategy for endemic schistosomiasis in a rural area of Bahia, Brazil. Adults were treated with a single dose (12.5 to 15 mg per kg) and children (less than 12 years old) with a total of 20 mg per kg in two doses. The 191 (infected) persons treated represented 69% of the infected population in the study area. Follow-up stool examinations (Kato-Katz method) at one, 3, 6, 13, 25 and 33 months showed the cure rate declining from 80% at three months to 46% at 33 months. Over one half of those not cured showed a decrease in egg counts throughout the follow-up which, after 33 months, remained 66% below the pre-treatment levels. Stool examinations conducted on all study area residents during three years before chemotherapy showed the prevalence and intensity of Schistosoma mansoni infection to be high and stable. 33 months after the chemotherapy the prevalence was 41% and for infected individuals the geometric mean egg count was 121 epg, a decline of respectively 35% and 40% from pre-treatment levels for each index. Chemotherapy of infected persons with oxamniquine protected the community as a whole from high worm burdens for almost three years, although at this point the prevalence began to rise towards pretreatment levels.

Relationship of electrocardiographic abnormalities and seropositivity to Trypanosoma cruzi within a rural community in northeast Brazil.

The relationship of infection with Trypanosoma cruzi to ECG abnormalities was studied in a defined population in rural Bahia, Brazil. Of 644 individuals 10 years of age or older who had complement fixation tests for antibodies to T. cruzi and ECGs, 53.7% were seropositive. ECG abnormalities were more common in seropositive individuals than in seronegative individuals, and more common in men than in women. The peak prevalence rate of abnormal ECGs occurred among seropositive individuals between 25 and 44 years of age; in this age group ECG abnormalities occurred 9.6 times more frequently among seropositive individuals than among seronegative individuals. The most common abnormalities were ventricular conduction defects, and right bundle branch block with or without fascicular block occurred in 10.7% of the infected population. PR intervals were longer in seropositive individuals than in seronegative individuals. Ventricular extrasystoles were slightly more common in seropositive individuals. A declining prevalence rate of abnormal ECGs among older seropositive individuals suggested selective mortality due to Chagas' heart disease.

Contribuicao ao conhecimento da microflora e microfauna de habitat de Biomphalaria glabrata (Say, 1818). / Microflora and microfauna of habitat of Biomphalaria glabrata (Say, 1818)

Os autores estudaram os componentes do microplancton em habitat de Biomphalaria glabrata (Say 1818), observando a nutricao e o crescimento dos planorbideos em situacoes de aumento e diminuicao da microflora e microfauna. Algumas especies de microalgas (Diatomaceas) foram encontradas no trato digestivo de B. glabrata, servindo-lhe de alimento. Atencao foi dispensada aos componentes da microflora e microfauna com apresentacao do quadro quantitativo, sistematica e ecologia das especies de Bacillariophyceae, Chorophyceae, Cyanophyceae, Euglenophyceae encontradas nas diversas amostras. As mais frequentes foram Nitzschia, Navicula, Pinnularia, Comphonema, Eunotia, Synedra, Hanitzchia, Cymbella A biometria dos planorbideos capturados nos varios meses de coleta mostra a ocorrencia de caramujos adultos e jovens, com riesgo do percentual de exemplares positivos para a liberacao de cercaria. Referencia tambem foi feita a biologia de Pistia stratiotes Linneu, entre outras plantas aquaticas que faziam parte da biocenose do charco situado na cidade de Castro Alves, Bahia